An LED element including a group-III nitride semiconductor that is formed on the front surface of a sapphire substrate and includes a light-emitting layer, a diffractive surface that is formed on the front surface of the sapphire substrate so that light emitted from the light-emitting layer is incident thereon and has depressions or projections whose period is larger than an optical wavelength of the light and is smaller than the coherence length of the light, and an Al reflective film that is formed on a back surface of the substrate so as to reflect the light diffracted by the diffractive surface so that the light is incident on the diffractive surface again is known (see Patent Literature 1). With this LED element, light transmitted by the diffraction effect is incident on the diffractive surface again and is transmitted through the diffractive surface again by the diffraction effect, whereby the light can be extracted outside the element in a plurality of modes.